Handling of dead fish is an imperative and important part of the daily routine at the fishing farms. The increasingly large constructions with 2-5000 tons of farmed biomass per location produces considerable amount of dead fish even during normal conditions. Removal of dead fish as quick as possible is crucial for reducing contaminations and risk of infections. The mortality rate in a fishing farm producing 4000 tons of mass may be as low as 1-2% per year, however it corresponds to 40-80 tons of dead fish per year. The clinical picture today with the spreading of fish diseases like PD (Pancreas Disease) and VHS (Viral Hemorrhagic Septicemia) provides an order to attend the risk that a mortality rate at between 50% and 70% in a generation may occur. During a disease outbreak in a part of the fish farm an imminent danger exists of infecting the remaining fish in the whole fishing farm. Depending on weather and wind and current condition may infectious fish constitute a risk of infection for every nearby fishing farm. As of today there are no proper systems with a capacity sufficient to handle large amounts of dead fish in rational way. Dead fish is loaded on minor working boats in trunks on board and transported to land where the trunks are unloaded to grinder tanks with varying capacity for grinding and adding of acid, for subsequently being pumped further to larger storage tanks. Working boats, their equipment and tanks may carry infection and contribute to spreading the infection on the way between the infected fish cage containing the dead or infectious fish, and the collecting or handling location on land. Under normal circumstances with a low mortality rate handling of dead fish is part of the daily routine work at fishing farms, but by a larger disease outbreak suddenly the workload is extremely huge and this may have impact on other tasks and the disease outbreak may easily turn to be prohibitively huge. Without effort over time the amounts of dead fish in net cages have tendency to accumulate, which is undesirable in many aspects, with regard to lacking of registration of the biomass, and increased risk of infection. If the dead fish is handled too late, it will constitute a poor raw material for ensiling. Handling of dead fish in large quantities may also incur an unpleasant and hard additional strain for the crew.
The vessel according to the present invention solves a number of problems related to handling of dead fish. The barge has a relatively small and easy cleaned surface of the deck and exposed surface of the equipment on the deck. The fish is brought to the inlet in that the barge is towed to the infected location and the dead fish is brought from the net cage up to the inlet funnel. The fish is immediately ground in the inlet arranged right after the funnel. The ground fish mass will thus pass the grinder device only once in contrast to traditional grinder pumps which generally must to run the mass several times through to make sure that all not yet ground rest materials are eventually ground. The ground mass after grinding is sent to the desired chemical treatment process, such as ensiling. The so chemically treated mass is stored in tanks until the mass in the tanks is pumped out and transported away in non-infectious condition. The barge according to the invention for treatment of dead fish is a compact and highly efficient device with vast capacity which will improve handling of dead fish, and may simplify the task of the fish farmers when considerable amounts of dead fish must be handled.